This invention relates to a stitching machine, and more particularly to a stitching machine having a multiple stroke looper mechanism.
Heretofore in the art of tufting, loop pile tufts are formed by one or more needles reciprocably driven to penetrate a moving base fabric to form a yarn loop on the opposite side of the base fabric, which is seized by a cooperating looper pointing in the same direction as the movement of the base fabric and having the same number of cyclical reciprocable strokes as the needle. In order to form cut pile tufts, a cut pile hook is substituted for each loop pile hook, but pointed in the opposite direction from the longitudinal direction of movement of the base fabric, to cooperate with a knife to cut the respective loops formed by the needle.
Chain stitching has been formed by a tufting machine, such as that disclosed in the Watkins U.S. Pat. No. 3,421,929, issued Jan. 14, 1969. However, in the Watkins patent, two loopers of different designs are used in cooperation with a laterally shifting yarn-supporting finger to operate on a single yarn to form a chain stitch. One of the loopers is a single-blade hook for seizing the yarn loop from the needle, while the other looper includes spaced prongs for spreading the seized loop for subsequent penetration by the needle.
In the Short U.S. Pat. No. 3,780,678, issued Dec. 25, 1973, a tufting machine is disclosed for forming loop pile in order to avoid the accidental formation of chain stitching, which Short considered undesirable. The Short patent also discusses the accidental and undesirable formation of chain stitching by other prior art tufting methods and apparatus.
The Watkins U.S. Pat. No. 3,401,657, issued Sept. 17, 1968, discloses a tufting machine for making chain stitches in which a pair of loopers alternately cooperate with a needle and each looper reciprocates at one-half the speed of the needle.
The Hash U.S. Pat. No. 4,285,286, issued Aug. 25, 1981, discloses a primary looper and a transfer looper for each needle, opposing each other and mounted on the same looper bar. The primary looper seizes the loop carried by the needle, and sequentially transfers the loop to the transfer looper which opens the loop for penetration by the needle on the next stroke, to form a chain-stitch. The loopers reciprocate at the same rate as the needle.